15-year follow-up of the Second Nordic Mantle Cell Lymphoma trial (MCL2): prolonged remissions without survival plateau

SOX11 is a novel binding partner and endogenous inhibitor of SAMHD1 ara-CTPase activity in mantle cell lymphoma

ABSTRACT

Sterile alpha motif and histidine-aspartate (HD) domain-containing protein 1 (SAMHD1) is a deoxynucleoside triphosphate triphosphohydrolase with ara-CTPase activity that confers cytarabine (ara-C) resistance in several hematological malignancies. Targeting SAMHD1's ara-CTPase activity has recently been demonstrated to enhance ara-C efficacy in acute myeloid leukemia. Here, we identify the transcription factor SRY-related HMG-box containing protein 11 (SOX11) as a novel direct binding partner and first known endogenous inhibitor of SAMHD1. SOX11 is aberrantly expressed not only in mantle cell lymphoma (MCL), but also in some Burkitt lymphomas. Coimmunoprecipitation of SOX11 followed by mass spectrometry in MCL cell lines identified SAMHD1 as the top SOX11 interaction partner, which was validated by proximity ligation assay. In vitro, SAMHD1 bound to the HMG box of SOX11 with low-micromolar affinity. In situ crosslinking studies further indicated that SOX11-SAMHD1 binding resulted in a reduced tetramerization of SAMHD1. Functionally, expression of SOX11 inhibited SAMHD1 ara-CTPase activity in a dose-dependent manner resulting in ara-C sensitization in cell lines and in a SOX11-inducible mouse model of MCL. In SOX11-negative MCL, SOX11-mediated ara-CTPase inhibition could be mimicked by adding the recently identified SAMHD1 inhibitor hydroxyurea. Taken together, our results identify SOX11 as a novel SAMHD1 interaction partner and its first known endogenous inhibitor with potentially important implications for clinical therapy stratification.

The addition of bortezomib to rituximab, high-dose cytarabine and dexamethasone in relapsed or refractory mantle cell lymphoma-a randomized, open-label phase III trial of the European mantle cell lymphoma network

The therapy of relapsed or refractory (r/r) mantle cell lymphoma (MCL) patients remains a major clinical challenge to date. We conducted a randomized, open-label, parallel-group phase-III trial hypothesizing superior efficacy of rituximab, high-dose cytarabine and dexamethasone with bortezomib (R-HAD + B) versus without (R-HAD) in r/r MCL ineligible for or relapsed after autologous stem cell transplant (ASCT). Primary endpoint was time to treatment failure (TTF), secondary endpoints included response rates, progression free survival, overall survival, and safety. In total, 128 of 175 planned patients were randomized to R-HAD + B (n = 64) or R-HAD (n = 64). Median TTF was 12 vs. 2.6 months (p = 0.045, MIPI-adjusted HR 0.69; 95%CI 0.47-1.02). Overall and complete response rates were 63 vs. 45% (p = 0.049) and 42 vs. 19% (p = 0.0062). A significant treatment effect was seen in the subgroup of patients >65 years (aHR 0.48, 0.29-0.79) and without previous ASCT (aHR 0.52, 0.28-0.96). Toxicity was mostly hematological and attributable to the chemotherapeutic backbone. Grade ≥3 leukocytopenia and lymphocytopenia were more common in R-HAD + B without differences in severe infections between both arms. Bortezomib in combination with chemotherapy can be effective in r/r MCL and should be evaluated further as a therapeutic option, especially if therapy with BTK inhibitors is not an option. Trial registration: NCT01449344.

Recent advancements in hematopoietic stem cell transplantation in Taiwan

Hematopoietic stem cell transplantation (HSCT) can cure malignant and nonmalignant hematological disorders. From 1983 to 2022, Taiwan performed more than 10,000 HSCT transplants. The Taiwan Blood and Marrow Transplantation Registry collects clinical information to gather everyone's experience and promote the advances of HSCT in Taiwan to gather everyone's experience and promote advances of HSCT in Taiwan. Compared with matched sibling donors, transplants from matched unrelated donors exhibited a trend of superior survival. In Taiwan, transplant donors showed remarkable growth from unrelated (24.8%) and haploidentical (10.5%) donors. The number of older patients (17.4%; aged ≥61 years) who underwent transplantation has increased markedly. This review summarizes several significant developments in HSCT treatment in Taiwan. First, the use of Anti-thymocyte globulin (ATG) and intravenous busulfan regimens were important risk factors for predicting hepatic sinusoidal obstruction syndrome. Second, a new, machine learning-based risk prediction scoring system for posttransplantation lymphoproliferative disorder has identified five risk factors: aplastic anemia, partially mismatched related donors, fludarabine use, ATG use, and acute skin graft-versus-host disease. Third, although the incidence of idiopathic pneumonia syndrome was low (1.1%), its mortality rate was high (58.1%). Fourth, difficult-to-treat mantle cell and T-cell lymphomas treated with autologous HSCT during earlier remission had higher survival rates. Fifth, treatment of incurable multiple myeloma with autologous HSCT showed a median progression-free survival and overall survival of 46.5 and 70.4 months, respectively. Sixth, different haploidentical transplantation strategies were compared. Seventh, caution should be taken in administering allogeneic HSCT treatment in older patients with myeloid leukemia with a Charlson Comorbidity Index ≥3 because of a higher risk of nonrelapse mortality.

SOHO State of the Art Updates and Next Questions: Treatment Evolution of Mantle Cell Lymphoma: Navigating the Different Entities and Biological Heterogeneity of Mantle Cell Lymphoma in 2024

Progress in mantle cell lymphoma (MCL) has led to significant improvement in outcomes of patients even in the real world (RW) setting albeit to a lesser degree. In parallel to the demonstration of benefit using combination therapy with rituximab plus high-dose cytarabine (R-AraC) as well as dose intensive therapy-autologous stem cell transplantation (DIT-ASCT) consolidation and maintenance, it became clear over the last 2 decades that MCL is a highly heterogenous disease at the molecular level, explaining differences observed in clinical behavior and response to therapy. While clinical prognostic factors and models have helped stratify patients with distinct outcomes, they failed to help guide therapy. The identification of molecular high-risk (HR) features, in particular, but not only, p53 aberrations (including mutations and deletions [del]), as well as complex karyotype (CK), has allowed to identify subsets of patients with poorer outcomes (median overall survival [OS] <2 years) regardless of conventional therapies used. The constant pattern of relapse seen in MCL has fueled sustained and productive efforts, with 7 novel agents approved in the United States (US), showing high and durable efficacy even in HR and chemo-refractory patients and likely curing a subset of patients in the relapsed or refractory (R/R) setting. Progress in diagnostics, in particular next-generation sequencing (NGS), which is accessible in routine practice nowadays, can help recognize patients with HR features, well beyond MIPI or Ki-67 prognostication, although the impact on decision making is still unclear. The era of integrating novel agents into our prior standard of care (SOC) has begun with a confirmed benefit, for example, ibrutinib (Ib) in the TRIANGLE study, defining the first new potential SOC in younger patients in over 30 years. Expanding on novel agents, either in combination, sequentially or to replace chemotherapy altogether, using biological doublets or triplets has led to a median progression-free survival (PFS) in excess of 72 months, certainly competitive with prior SOC and will continue to reshape the management of MCL patients. Achieving minimal residual disease negative (MRD-ve) status is becoming a new endpoint in MCL, and customizing maintenance and/or de-escalation/consolidation strategies is within reach, although it will require prospective, built-in MRD-based approaches, with the goal of eliminating subclinical disease and not simply delaying time to relapse. Taking into account the biological diversity of MCL is now feasible in routine clinical practice and has already helped recognize what not to do for HR patients (i.e., avoid intensive induction chemotherapy and/or ASCT for p53 mutated patients) as well as identify promising novel options. Ongoing and future work will help expand on these dedicated approaches, to further improve the management and outcomes of all MCL patients.

SOX11 is a novel binding partner and endogenous inhibitor of SAMHD1 ara-CTPase activity in mantle cell lymphoma

The sterile alpha motif and histidine-aspartate (HD) domain containing protein 1 (SAMHD1) is a deoxynucleoside triphosphate triphosphohydrolase with ara-CTPase activity that confers cytarabine (ara-C) resistance in several haematological malignancies. Targeting SAMHD1's ara-CTPase activity has recently been demonstrated to enhance ara-C efficacy in acute myeloid leukemia. Here, we identify the transcription factor SRY-related HMG-box containing protein 11 (SOX11) as a novel direct binding partner and first known endogenous inhibitor of SAMHD1. SOX11 is aberrantly expressed not only in mantle cell lymphoma (MCL), but also in some Burkitt lymphomas. Co-immunoprecipitation of SOX11 followed by mass spectrometry in MCL cell lines identified SAMHD1 as the top SOX11 interaction partner which was validated by proximity ligation assay. In vitro, SAMHD1 bound to the HMG box of SOX11 with low-micromolar affinity. In situ crosslinking studies further indicated that SOX11-SAMHD1 binding resulted in a reduced tetramerization of SAMHD1. Functionally, expression of SOX11 inhibited SAMHD1 ara-CTPase activity in a dose-dependent manner resulting in ara-C sensitization in cell lines and in a SOX11-inducible mouse model of MCL. In SOX11-negative MCL, SOX11-mediated ara-CTPase inhibition could be mimicked by adding the recently identified SAMHD1 inhibitor hydroxyurea. Taken together, our results identify SOX11 as a novel SAMHD1 interaction partner and its first known endogenous inhibitor with potentially important implications for clinical therapy stratification.

Survival Outcomes of Patients with Mantle Cell Lymphoma: A Retrospective, 15-Year, Real-Life Study

Mantle cell lymphoma (MCL) prognosis has significantly improved in recent years; however, the possible survival benefit of new treatment options should be evaluated outside of clinical trials. We investigated 73 consecutive MCL patients managed from 2006 to 2020. For younger patients <65 years old, the median PFS was 72 months and we reported a 2-year, 5-year, and 10-year PFS of 73%, 62%, and 41%; median OS was not reached and we reported a 2-year, 5-year, and 10-year OS of 88%, 82%, and 66%. For patients aged 75 years or older, the median PFS was 36 months and we reported a 2-year, 5-year, and 10-year PFS of 52%, 37%, and 37%; median OS was not reached and we reported a 2-year, 5-year, and 10-year OS of 72%, 55%, and 55%. The median PFS was significantly reduced for patients treated between 2006 and 2010 compared to patients treated between 2011 and 2015 (p = 0.04). Interestingly, there was a trend towards improved OS for patients treated between 2016 and 2020 compared to between 2006 and 2010 and between 2011 and 2015 (5-year OS was 91%, 44%, and 33%). These findings could be due to the introduction of BR as a first-line regimen for elderly patients and to the introduction of ibrutinib as a second-line regimen.

Genetic and prognostic analysis of blastoid and pleomorphic mantle cell lymphoma: a multicenter analysis in China

Blastoid or pleomorphic mantle cell lymphoma (B/P-MCL) is characterized by high invasiveness and unfavorable outcomes, which is still a challenge for treating MCL. This retrospective study was performed to comprehensively analyze the clinical, genomic characteristics and treatment options of patients with B/PMCL from multicenter in China. Data were obtained from 693 patients with B/PMCL from three centers in China between April 1999 and December 2019. Seventy-four patients with BMCL (n = 43) or PMCL (n = 31) were included in the analysis. The median age of the cohort was 60.0 years with a male-to-female ratio of 2.89:1. The 3-year progression-free survival (PFS) and overall survival (OS) rates were 44.1% and 46.0%, respectively. Mutations of TP53, ATM, NOTCH1, NOTCH2, NSD2, SMARCA4, CREBBP, KMT2D, FAT1, and TRAF2 genes were the most common genetic changes in B/P-MCL. Progression of disease within 12 months (POD12) could independently predict the poor prognosis of patients with blastoid and pleomorphic variants. Patients with POD12 carried a distinct mutation profile (TP53, SMARCA4, NSD2, NOTCH2, KMT2D, PTPRD, CREBBP, and CDKN2A mutations) compared to patients with non-POD12. First-line high-dose cytosine arabinoside exposure obtained survival benefits in these populations, and BTKi combination therapy as the front-line treatment had somewhat improvement in survival with no significant difference in the statistic. In conclusion, B/P-MCL had inferior outcomes and a distinct genomic profile. Patients with POD12 displayed a distinct mutation profile and a poor prognosis. New therapeutic drugs and clinical trials for B/P-MCL need to be further explored.

Novel treatment for mantle cell lymphoma - impact of BTK inhibitors and beyond

Mantle cell lymphoma (MCL) primarily affects older adults, accounting for 3-10% of all non-Hodgkin lymphoma (NHL) in western countries. The disease course of MCL is heterogenous; driven by clinical, cytogenetics, and molecular features that shape differences in outcomes, including proliferation index, MIPI scores, and mutational profile such as TP53 aberration. The advent of novel agents has fundamentally evolved the treatment landscape for MCL with treatment strategies that can now be more effectively tailored based on both patient- and disease-specific factors. In this review, we discuss the major classes of novel agents used for the treatment of MCL, focusing on efficacy and notable toxicities of BTK inhibitors. We further examine effective novel combination regimens and, lastly, discuss future directions for the evolution of targeted approaches for the treatment of MCL.

Recent advances in genomics and therapeutics in mantle cell lymphoma

Over the past decades, significant strides have been made in understanding the pathobiology, prognosis, and treatment options for mantle cell lymphoma (MCL). The heterogeneity observed in MCL's biology, genomics, and clinical manifestations, including indolent and aggressive forms, is intricately linked to factors such as the mutational status of the variable region of the immunoglobulin heavy chain gene, epigenetic profiling, and Sox11 expression. Several intriguing subtypes of MCL, such as Cyclin D1-negative MCL, in situ mantle cell neoplasm, CCND1/IGH FISH-negative MCL, and the impact of karyotypic complexity on prognosis, have been explored. Notably, recent immunochemotherapy regimens have yielded long-lasting remissions in select patients. The therapeutic landscape for MCL is continuously evolving, with a shift towards nonchemotherapeutic agents like ibrutinib, acalabrutinib, and venetoclax. The introduction of BTK inhibitors has brought about a transformative change in MCL treatment. Nevertheless, the challenge of resistance to BTK inhibitors persists, prompting ongoing efforts to discover strategies for overcoming this resistance. These strategies encompass non-covalent BTK inhibitors, immunomodulatory agents, BCL2 inhibitors, and CAR-T cell therapy, either as standalone treatments or in combination regimens. Furthermore, developing novel drugs holds promise for further improving the survival of patients with relapsed or refractory MCL. In this comprehensive review, we methodically encapsulate MCL's clinical and pathological attributes and the factors influencing prognosis. We also undertake an in-depth examination of stratified treatment alternatives. We investigate conceivable resistance mechanisms in MCL from a genetic standpoint and offer precise insights into various therapeutic approaches for relapsed or refractory MCL.

Allogeneic stem cell transplantation achieves long-term remissions in mantle cell lymphoma, including in TP53-mutated disease

Cytarabine-containing chemoimmunotherapy followed by autologous transplantation and rituximab maintenance achieves durable remissions for most patients with mantle cell lymphoma (MCL). However, patients with TP53-mutated disease have poor outcomes with standard approaches. We previously reported that allogeneic stem cell transplantation (alloSCT) achieved durable remissions in MCL, however follow-up among patients with TP53-mutated disease was limited. Here we report extended follow-up of the overall cohort (n = 36) and TP53-mutated subset (n = 13) (median follow-up 10.8 and 4.2 years, respectively). Estimated overall survival was 56% at 10 years for the overall cohort and 59% at 4 years for the TP53-mutated subset. Among patients with TP53-mutated disease, no relapses occurred beyond 6 months post-transplant. Survival after post-alloSCT disease relapse was poor (median 2.1 years). These data confirm that alloSCT can be curative in MCL, including patients with TP53-mutated disease, and should be considered for earlier utilization in this subgroup for whom conventional chemoimmunotherapy is ineffective.

The addition of rituximab to chemotherapy improves overall survival in mantle cell lymphoma-a pooled trials analysis

Mantle cell lymphoma (MCL) is a distinct subtype of B-cell lymphoma and commonly used induction immunochemotherapies include the anti-CD20 antibody rituximab. However, efficacy data for rituximab regarding overall survival (OS) in first line MCL therapy remain conflicting.We report long-term outcomes of a pooled trials analysis comparing Cyclophosphamide, Doxorubicine, Vincristine, Prednisone (CHOP) to R-CHOP in MCL to confirm efficacy on failure free survival (FFS) and OS in relevant subgroups. Untreated, adult MCL patients of two prospective trials assigned to CHOP or R-CHOP were included. Primary endpoints were FFS and OS, secondary endpoints included duration of response (DOR), secondary malignancies and OS after relapse. Between 1996 and 2003, 385 MCL patients were assigned to CHOP (201) or R-CHOP (184). After a median follow-up of 13.4 years, the addition of Rituximab significantly improved FFS (1.36 vs. 2.07 years, HR 0.62 (0.50-0.77)), OS (4.84 vs. 5.81 years, HR 0.78 (0.61-0.99)) and DOR (1.48 vs. 2.08 years, HR 0.67 (0.53-0.86)). Furthermore, Rituximab improved survival across different MCL risk groups. In a post-hoc analysis of OS after relapse comparing patients receiving chemotherapy with / without rituximab, rituximab maintained efficacy with a median OS of 3.10 vs. 2.11 years (HR 0.70, 0.54-0.91). The rate of secondary malignancies was 0.5 and 3.9% for hematological and 7 and 8% for non-hematological malignancies for CHOP and R-CHOP patients, respectively. We present mature results of a pooled MCL cohort, demonstrating prolonged FFS, OS and DOR for the combined immuno-chemotherapy, confirming the standard of care in first line treatment.

Up-Front ASCT Overcomes the Survival Benefit Provided by HDAC-Based Induction Regimens in Mantle Cell Lymphoma: Data from a Real-Life and Long-Term Cohort

BACKGROUND

Mantle cell lymphoma (MCL) is a rare malignancy with heterogeneous behavior. Despite the therapeutic advances recently achieved, MCL remains incurable. Currently, the standard of care for young and fit patients involves induction immunochemotherapy followed by up-front autologous stem cell transplantation (ASCT). However, the role of more intensive induction regimens, such as those based on high doses of cytarabine (HDAC), remains controversial in the management of ASCT-eligible patients.

METHODS

This retrospective, observational, and single-center study involved 165 MCL patients treated at the largest oncology center in Latin America from 2010 to 2022. We aimed to assess outcomes, determine survival predictors, and compare responses between different primary therapeutic strategies, with a focus on assessing the impact of HDAC-based regimens on outcomes in ASCT-eligible patients.

RESULTS

The median age at diagnosis was 65 years (38-89 years), and 73.9% were male. More than 90% of the cases had a classic nodal form (cnMCL), 76.4% had BM infiltration, and 56.4% presented splenomegaly. Bulky ≥ 7 cm, B-symptoms, ECOG ≥ 2, and advanced-stage III/IV were observed in 32.7%, 64.8%, 32.1%, and 95.8%, respectively. Sixty-four percent of patients were categorized as having high-risk MIPI. With a median follow-up of 71.1 months, the estimated 2-year OS and EFS were 64.1% and 31.8%, respectively. Patients treated with (R)-HDAC-based regimens had a higher ORR (85.9% vs. 65.7%, p = 0.007) compared to those receiving (R)-CHOP, as well as lower POD-24 rates (61.9% vs. 80.4%, p = 0.043) and lower mortality (43.9% vs. 68.6%, p = 0.004). However, intensified induction regimens with (R)-HDAC were not associated with a real OS benefit in MCL patients undergoing up-front consolidation with ASCT (2-year OS: 88.7% vs. 78.8%, p = 0.289). Up-front ASCT was independently associated with increased OS (p < 0.001), EFS (p = 0.005), and lower POD-24 rates (p < 0.001) in MCL. Additionally, CNS infiltration, TLS, hypoalbuminemia, and the absence of remission after induction were predictors of poor OS.

CONCLUSIONS

In the largest Latin American cohort of MCL patients, we confirmed the OS benefit promoted by up-front consolidation with ASCT in young and fit patients, regardless of the intensity of the immunochemotherapy regimen used in the pre-ASCT induction. Although HDAC-based regimens were not associated with an unequivocal increase in OS for ASCT-eligible patients, it was associated with higher ORR and lower rates of early relapses for the whole cohort.

Treatment of older patients with mantle cell lymphoma in the era of novel agents

Mantle cell lymphoma (MCL) is a rare, B-cell non-Hodgkin's lymphoma with a highly heterogeneous presentation that ranges from an indolent disease to an extremely aggressive one. Several clinical and biological prognostic markers can assist in determining the aggressiveness of the disease. Such as MIPI, Ki-67, and TP53, NOTCH1, and CDKN2A mutations. While aggressive chemoimmunotherapy regimens combining rituximab and cytarabine, followed by autologous stem-cell transplantation yield the most promising results, this treatment is too toxic for older patients. Several lower-intensity regimens have shown efficacy in older patients with reduced toxicity profiles. However, older relapsed/refractory patients have an extremely poor outcome. In the last several years, there is a major trend toward chemotherapy-free regimens, targeted therapies such as BTK, BCL-2 and PI3K inhibitors, and immunotherapies such as lenalidomide and CAR-T, which can provide a promising strategy for older patients. Herein we review the current therapies for older MCL patients, chemotherapy regimens, targeted therapies, and immunotherapies.

Time to progression of disease and outcomes with second-line BTK inhibitors in relapsed/refractory mantle cell lymphoma

Time to progression of disease (POD) after first-line (1L) therapy is prognostic in mantle cell lymphoma (MCL), although studies have included a broad range of 1L, second-line (2L), and subsequent lines of therapy. The purpose of this study was to evaluate the factors predicting outcomes in patients with relapsed/refractory (R/R) MCL exclusively initiating 2L Bruton's tyrosine kinase inhibitors (BTKis) after 1L rituximab-containing therapy. Patients were accrued from 8 international centers (7 main, 1 validation cohort). Multivariable models evaluating the association between time to POD and clinical/pathologic factors were constructed and converted into nomograms and prognostic indexes predicting outcomes in this population. A total of 360 patients were included, including 160 in the main cohort and 200 in the validation cohort. Time to POD, Ki67 ≥ 30%, and MCL International Prognostic Index (MIPI) were associated with progression-free survival (PFS2) and overall survival (OS2) from the start of 2L BTKis. C-indexes were consistently ≥0.68 in both cohorts. Web/application-based calculators based on nomograms and prognostic indexes to estimate PFS2 and OS2 were constructed. The 2L BTKi MIPI identifies 3 groups with distinct 2-year PFS2, including high risk (14%), intermediate risk (50%), and low risk (64%). Time to POD, Ki67, and MIPI are associated with survival outcomes in patients with R/R MCL receiving 2L BTKis. Simple clinical models incorporating these variables may assist in planning for alternative therapies such as chimeric antigen receptor T-cell therapy, allogeneic stem cell transplantation, or novel agents with alternative mechanisms of action.

Adding venetoclax to lenalidomide and rituximab is safe and effective in patients with untreated mantle cell lymphoma

Mantle cell lymphoma (MCL) is a rare, incurable hematological malignancy with a heterogeneous presentation and clinical course. A wide variety of chemotherapy-based regimens are currently used in patients who are untreated. Over the last several years, several targeted or small-molecule therapies have shown efficacy in the relapsed/refractory setting and have since been explored in the frontline setting. Lenalidomide plus rituximab was explored in a phase 2 study of 38 patients with MCL who were untreated and ineligible to receive transplantation, in which the combination produced durable remissions. We looked to build upon this regimen by adding venetoclax to the combination. We conducted a multicenter, open-label, nonrandomized, single-arm study to evaluate this combination. We enrolled 28 unselected patients with untreated disease irrespective of age, fitness, or risk factors. Lenalidomide was dosed at 20 mg daily from days 1 to 21 of each 28-day cycle. The dose of venetoclax was determined using the time-to-event continual reassessment method. Rituximab was dosed at 375 mg/m2 weekly, starting on cycle 1, day 1 until cycle 2, day 1. No dose-limiting toxicities were noted. All patients were treated with venetoclax at the maximum tolerated dose of 400 mg daily. The most common adverse events were neutropenia and thrombocytopenia. The overall and complete response rates were 96% and 86%, respectively. In total, 86% of patients achieved minimal residual disease undetectability via next-generation sequencing. The median overall and progression-free survivals were not reached. The combination of lenalidomide, rituximab, and venetoclax is a safe and effective regimen in patients with untreated MCL. This trial was registered at www.clinicaltrials.gov as #NCT03523975.

Exploring new prognostic biomarkers in Mantle Cell Lymphoma: a comparison of the circSCORE and the MCL35 score

Mantle cell lymphoma (MCL) is a biologically and clinically heterogeneous disease, emphasizing the need for prognostic biomarkers. In this study we aimed at comparing the prognostic value of two RNA-based risk scores, circSCORE and MCL35, in 149 patients from the MCL2 (ISRCTN87866680) and MCL3 (NCT00514475) patient cohorts. Both risk scores provided significant stratification of high versus low risk for progression free survival (PFS) and overall survival (OS). The circSCORE retained significant prognostic value in adjusted multivariable Cox regressions for PFS, but not for OS. Furthermore, circSCORE added significant prognostic value to MIPI in the pooled cohort (MCL2 and MCL3) for PFS and OS, and for PFS in MCL3 alone, outperforming Ki67 and MCL35. We suggest a new, combined MIPI-circSCORE with improved prognostic value, and with potential for future clinical implementation, if validated in a larger, independent cohort.

Real-world treatment and outcome patterns of patients with mantle cell lymphoma in China: A large, multicenter retrospective analysis

BACKGROUND

Mantle cell lymphoma (MCL) is an uncommon heterogeneous subtype of B cell non-Hodgkin lymphoma, and clinical features in MCL appear regional characteristics. MCL treatment opinions are not uniform between countries or regions within Asia and China, and Asian patient-specific data for MCL treatment are fewer. The study aims to explore the clinical characteristics, treatment patterns and prognosis of MCL patients in China.

METHODS

A total of 805 patients diagnosed with MCL between April 1999 and December 2019 at 19 comprehensive hospitals in China were included in this retrospective analysis. Kaplan-Meier method coupled with the log-rank test was used for univariate analysis, and COX proportional hazards model was used for multivariate analysis (MVA). p < 0.05 was consided statistically significant. All outputs were produced using R version 4.1.0.

RESULTS

The median age of the cohort was 60.0 years with a male-to-female ratio of 3.36:1. Five-year progression-free survival (PFS) and overall survival (OS) rates were 30.9% and 65.0%, respectively. High-intermediate/high-risk group according to MIPI-c, without high-dose cytarabine, lack of Auto-SCT as consolidation and maintenance treatment and SD/PD in initial treatment remained statistically relevant to poor PFS on MVA, and ki67 ≥50%, B symptoms, high-intermediate/high risk group according to MIPI-c, without high-dose cytarabine, lack of maintenance treatment, SD/PD in initial treatment and relapse/refractory state were independently associated with poorer OS on MVA.

CONCLUSIONS

First-line high dose cytarabine exposure, auto-SCT as consolidation therapy obtained survival benefits in Chinese population. Our study further confirmed the value of maintenance treatment and explored the application of new drug treatment and bendamustine in R/R MCL patients.

Bendamustine/Rituximab Plus Cytarabine/Rituximab, With or Without Acalabrutinib, for the Initial Treatment of Transplant-Eligible Mantle Cell Lymphoma Patients: Pooled Data From Two Pilot Studies

INTRODUCTION

Mantle cell lymphoma (MCL) is a moderately aggressive lymphoma subtype, generally viewed as incurable. For younger, fit patients, the standard of care remains various high-dose cytarabine-based induction regimens followed by autologous hematopoietic cell transplant and 3 years of rituximab maintenance. Despite reasonably good outcomes, with median progression-free survival in the range of 7 to 9 years, most patients eventually relapse, indicating a need to improve the safety and tolerability of remission induction strategies.

METHODS

Given the impressive activity of bendamustine/rituximab (BR) in older patients with MCL, we developed an induction regimen modeled after the Nordic Regimen but substituted BR in place of R-CHOP. In a second pilot study, we incorporated the second-generation Bruton tyrosine kinase inhibitor (BTKi), acalabrutinib, into the regimen. The primary endpoint of both studies was stem cell mobilization success rate.

RESULTS

All patients successfully underwent stem cell harvest in both studies.

CONCLUSION

The experience from our single institution pilot study suggested that sequential rather than alternating BR and cytarabine/rituximab (CR) was easier to administer from the standpoint of toxicities and subsequent dose modifications. Safety and efficacy data from the 2 pilot studies, FitMCL 1.0 and 2.0, were similar. The pilot studies provided preliminary safety data supporting the development of the NCTN trial EA4181, assessing three different induction regimens with or without acalabrutinib.

Long-term outcome in patients with mantle cell lymphoma following high-dose therapy and autologous stem cell transplantation

BACKGROUND

Long-term clinical and molecular remissions in patients with mantle cell lymphoma (MCL) after autologous stem cell transplantation (ASCT) have been evaluated in only a few studies.

DESIGN AND METHODS

Sixty-five patients with MCL received ASCT (54 first-line ASCT, 10 second-line ASCT, and 1 third-line ASCT). In the case of long-term remission (≥5 years; n = 27), peripheral blood was tested for minimal residual disease (MRD) by t(11;14)- and IGH-PCR at the last follow-up.

RESULTS

Ten-year overall survival (OS), progression-free survival (PFS), and freedom from progression (FFP) after first-line ASCT were 64%, 52%, and 59% versus after second-line ASCT 50%, 20%, and 20%, respectively. Five-year OS, PFS, and FFP for the first-line cohort were 79%, 63%, and 69%, respectively. Five-year OS, PFS, and FFP after second-line ASCT were 60%, 30%, and 30%, respectively. Treatment-related mortality (3 months after ASCT) was 1.5%. So far 26 patients developed sustained long-term clinical and molecular complete remissions of up to 19 years following ASCT in first treatment line.

CONCLUSION

Sustained long-term clinical and molecular remissions are achievable following ASCT.

How I manage mantle cell lymphoma: indolent versus aggressive disease

Mantle cell lymphoma (MCL) is a mature B-cell lymphoma with a variable clinical course and historically poor prognosis. Management is challenging in part due to the heterogeneity of the disease course, with indolent and aggressive subtypes now well recognised. Indolent MCL is often characterised by a leukaemic presentation, SOX11 negativity and low proliferation index (Ki-67). Aggressive MCL is characterised by rapid onset widespread lymphadenopathy, extra-nodal involvement, blastoid or pleomorphic histology and high Ki-67. Tumour protein p53 (TP53) aberrations in aggressive MCL are recognised with clear negative impact on survival. Until recently, trials have not addressed these specific subtypes separately. With the increasing availability of targeted novel agents and cellular therapies, the treatment landscape is constantly evolving. In this review, we describe the clinical presentation, biological factors, and specific management considerations of both indolent and aggressive MCL and discuss current and potential future evidence which may help move to a more personalised approach.

Personalized approaches for treatment-naïve mantle cell lymphoma

INTRODUCTION

Mantle cell lymphoma (MCL) can have diverse disease presentations, which vary in aggressiveness and prognosis, and can occur in patients with varying ability to tolerate therapy. Additionally, the options for treatment of MCL have expanded rapidly in the last decade, translating to improved outcome for patients.

AREAS COVERED

We review the initial evaluation of patients with MCL, identifying disease- and patient-specific prognostic factors, along with personalized therapies for patients with MCL. Specific scenarios include indolent and limited-stage MCL, advanced-stage disease in transplant-eligible and ineligible patients, and high-risk TP53 mutant disease. Ongoing trials and future directions in MCL treatment are also highlighted.

EXPERT OPINION

Given the wide array of disease and patient presentations with MCL, a personalized therapeutic approach is needed to optimize outcomes. The best therapeutic strategy should incorporate disease prognostic factors, patient status and comorbidities, goals of care, and response to treatment.

Treatment approaches for patients with TP53-mutated mantle cell lymphoma

Mantle cell lymphoma is an uncommon subtype of lymphoma characterised by clinical and biological heterogeneity. Although most patients with mantle cell lymphoma have durable responses after chemoimmunotherapy, there is a need to prospectively identify high-risk subsets of patients for whom disease control with standard chemotherapy will be short lived. Among the available prognostic factors, TP53 mutations are uniquely informative owing to their strong association with early disease progression and death among patients receiving conventional chemoimmunotherapy, with the highest negative prognostic value compared with other established risk indicators, including the mantle cell lymphoma international prognostic index, histological features, elevated Ki-67, and other genetic lesions. The poor outcomes for patients with TP53-mutated mantle cell lymphoma receiving chemoimmunotherapy and second-line Bruton tyrosine kinase inhibitors represent an urgent need for alternative approaches. In this Review, we synthesise the available data to inform the management of this high-risk subset of patients and present a treatment strategy prioritising clinical trials and early use of cellular therapies.

Frontline Therapy in Mantle Cell Lymphoma: When Clinical Trial and Real-World Data Collide

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.A large number of frontline treatment options exist for mantle cell lymphoma (MCL), making selection of therapy a challenge for the clinician. In this Oncology Grand Rounds article, the case of a 73-year-old woman with MCL who attained remission with bendamustine and rituximab is presented. The relevant literature regarding frontline therapy is then reviewed, with particular focus on selection of induction regimen and the potential roles for autologous transplantation and/or rituximab maintenance. This literature primarily consists of prospective phase 2 and phase 3 clinical trials; however, added to this literature now is a growing body of large retrospective real-world cohorts, such as the new analysis by Martin et al,³⁵ the manuscript that accompanies this Oncology Grand Rounds article. In some cases, the real-world evidence is at odds with data from prospective clinical trials, such as regarding the role of rituximab maintenance after bendamustine plus rituximab induction. These important new real-world data are put into context of an ever-changing treatment landscape, in hopes of aiding clinicians in frontline treatment selection for patients with MCL.

Concurrent Inhibition of Akt and ERK Using TIC-10 Can Overcome Venetoclax Resistance in Mantle Cell Lymphoma

Venetoclax, a BCL-2 inhibitor, has proven to be effective in several hematological malignancies, including mantle cell lymphoma (MCL). However, development of venetoclax resistance is inevitable and understanding its underlying molecular mechanisms can optimize treatment response. We performed a thorough genetic, epigenetic and transcriptomic analysis of venetoclax-sensitive and resistant MCL cell lines, also evaluating the role of the stromal microenvironment using human and murine co-cultures. In our model, venetoclax resistance was associated with abrogated TP53 activity through an acquired mutation and transcriptional downregulation leading to a diminished apoptotic response. Venetoclax-resistant cells also exhibited an upregulation of the PI3K/Akt pathway, and pharmacological inhibition of Akt and ERK with TIC-10 led to cell death in all venetoclax-resistant cell lines. Overall, we highlight the importance of targeted therapies, such as TIC-10, against venetoclax resistance-related pathways, which might represent future therapeutic prospects.

Survival of patients with mantle cell lymphoma in the rituximab era: Retrospective binational analysis between 2000 and 2020

Mantle cell lymphoma (MCL) is a rare peripheral B-cell lymphoma characterised by eventual relapse and progression towards a more aggressive disease biology. With the introduction of rituximab- and cytarabine-based immunochemotherapy regimens, the prognosis of the disease has changed dramatically over the last two decades. To assess the real-world survival of patients with MCL, we used a population-based cohort of 564 patients with MCL who were diagnosed and treated between 2000 and 2020. Patient data were collected from seven Finnish treatment centres and one Spanish treatment centre. For the entire patient population, we report a 2-year overall survival (OS) rate of 77%, a 5-year OS of 58%, and a 10-year OS of 32%. The estimated median OS was 80 months after diagnosis. MCL is associated with increased mortality across the entire patient population. Additionally, we assessed the survival of patients after MCL relapse with the aim of establishing a cut-off point of prognostic significance. Based on our statistical analysis of survival after the first relapse, disease progression within 24 months of the initial diagnosis should be considered as a strong indicator of poor prognosis.

What is the role of up-front autologous stem cell transplantation in mantle cell lymphoma?

Up-front autologous stem cell transplantation (ASCT) is the established standard of care for younger, transplant-eligible MCL patients and is associated with a prolonged progression-free survival (PFS) benefit. However, there is no randomized controlled trial data, with therapy including rituximab and cytarabine, that has established a PFS and overall survival (OS) benefit with ASCT in the modern era. Multiple retrospective studies have failed to identify an OS benefit associated with ASCT in younger MCL patients. The high-risk patient subgroup with evidence of baseline TP53 mutation has a dismal outcome with intensive chemoimmunotherapy followed by ASCT, thus up-front ASCT is not optimal for this patient subset. Ongoing randomized clinical trials will help to clarify the role of up-front ASCT in the future. For example, the ongoing European MCL Network Triangle study incorporating ibrutinib into chemoimmunotherapy induction and maintenance with and without ASCT will help define the role of ASCT in the era of novel biologically targeted agents (ClinicalTrials.gov identifier: NCT02858258). Additionally, minimal residual disease (MRD) assessment is a powerful prognostic tool in MCL, and the ongoing Eastern Cooperative Oncology Group-American College of Radiology Imaging Network E4151 study is comparing maintenance rituximab alone vs ASCT consolidation in MCL patients who achieve remission and MRD-undetectable status post induction (ClinicalTrials.gov identifier: NCT03267433). ASCT remains a highly efficacious initial therapy for younger MCL patients; however, ultimately the decision to pursue ASCT requires discussion of risks vs benefits, incorporating patient preferences and values.

BRUIN MCL-321: phase III study of pirtobrutinib versus investigator choice of BTK inhibitor in BTK inhibitor naive mantle cell lymphoma

Treatment with covalent Bruton tyrosine kinase inhibitors (BTKi) represents an important advance in the management of relapsed or refractory mantle cell lymphoma, but these treatments are not curative and many patients ultimately relapse. Pirtobrutinib, a highly selective, noncovalent (reversible) BTKi, inhibits both wild type and C481-mutant BTK with equal low nM potency, and has favorable oral pharmacology that enables continuous BTK inhibition throughout the dosing interval regardless of intrinsic rate of BTK turnover. Pirtobrutinib is well tolerated and has demonstrated promising efficacy in patients with poor prognosis B-cell malignancies following prior therapy, including covalent BTKi. This phase III, head-to-head, randomized study (NCT04662255) will evaluate whether pirtobrutinib is superior to investigator's choice of covalent BTKi in patients with previously treated, BTKi-naive mantle cell lymphoma.

Treatment of Mantle Cell Lymphoma in the Frontline Setting: Are We Ready for a Risk-Adapted Approach?

Mantle cell lymphoma (MCL), a type of B-cell non-Hodgkin lymphoma characterized by the t(11;14)(q13q32) translocation, is a clinically heterogenous disease which can range from indolent to highly aggressive. Numerous prognostic factors have been identified, including blastoid histology, the Mantle Cell Lymphoma International Prognostic Index (MIPI) score, high proliferation index, p53 deletions and/or mutations, complex karyotype, minimal residual disease, and several others. However, using these prognostic factors to guide treatment selection has largely remained elusive. Given the heterogeneous behavior of this disease and varying patient characteristics, we suggest that the time has come for a more risk-adapted approach to this disease. In this article, we review the numerous prognostic factors that have been described for MCL, both at the time of diagnosis and following first-line treatment. We then propose a risk-adapted approach to first-line therapy for MCL, which would reserve intensive therapy for the highest risk patients and spare others excessive toxicity.

USP9X Increased Tumor Angiogenesis in Mantle Cell Lymphoma by Upregulation of CCND1-Mediated SOX11

Mantle cell lymphoma (MCL) is an aggressive lymphoid malignancy with a poor prognosis. Ubiquitin-specific peptidase 9, X-linked (USP9X), has been associated with multiple physiological pathways and regulates various cellular activities. In this study, we explored the role of USP9X in MCL in vitro and in vivo. USP9X was verified to be increased in peripheral blood mononuclear cells (PBMCs) of MCL patients and MCL cells. Moreover, CCND1 and SOX11 were also upregulated in PBMCs of MCL patients. The positive correlation between USP9X and CCND1, USP9X and SOX11, and CCND1 and SOX11 were identified. Further, USP9X overexpression and knockdown were performed in MCL cells. We proved that USP9X overexpression promoted proliferation and cell cycle and suppressed cell apoptosis in MCL cells. Upregulation of angiogenesis and cell migration were induced by USP9X overexpression in MCL cells. However, the USP9X knockdown showed opposite effects. In addition, USP9X was discovered to decrease Cyclin D1 (CCND1)-mediated SOX11 expression in MCL cells. We demonstrated that SOX11 overexpression reversed USP9X knockdown-mediated angiogenesis in MCL cells. Besides, tumor formation was inhibited by USP9X knockdown in mice in vivo. In conclusion, these results revealed that USP9X promoted tumor angiogenesis in MCL via increasing CCND1-mediated SOX11.

Mantle Cell Lymphoma: the Role of Risk-Adapted Therapy and Treatment of Relapsed Disease

PURPOSE OF REVIEW

In this review, the current treatment strategies are recapped, evolving agents are discussed, and we provide guidance in treating R/R MCL.

RECENT FINDINGS

There has been an advancement in treatment using targeted therapy, cellular therapies including chimeric antigen receptor (CAR) T cell therapy and hematopoietic stem cell transplantation (HSCT) and novel therapeutic agents including non-covalent BTKis, bispecific antibodies, and antibody-drug conjugates for treatment of refractory and relapsed mantle cell lymphoma. Mantle cell lymphoma (MCL) is a mature B-cell lymphoma that is associated with a poor prognosis. Current treatments include immunochemotherapy, chemotherapy and autologous stem cell transplantation (SCT) which place patients in remission but result in relapse. Chemoimmunotherapy uses chemotherapeutic agents paired with rituximab in patients who have chemo-sensitive disease with prolonged remission of at least > 2 years and/or have contraindications to chemotherapy that serve as bridges to more definitive treatment. Additional therapies including proteosome inhibitor-based therapies and immunomodulators, like bortezomib and lenalidomide, can be used as single agents or in combination with others. Bruton's tyrosine kinase (BTK) inhibitors including ibrutinib, acalaburtinib, and zanubrutinib have also been proven effective for the treatment of (R/R) disease. Another agent is Venetoclax, a robust drug that can be used in MCL after progression or intolerance to BTKi. Newer advances in the management of MCL have led to the utilization of cellular therapies including chimeric antigen receptor (CAR) T cell therapy and SCT that are options for healthy young (< 65 years old) who have progressed through several lines of therapies. With progression of disease, mutations are acquired that cause therapy resistance. Novel therapeutic agents such as non-covalent BTKis, bispecific antibodies, and antibody-drug conjugates are paving the way for advancements in treatment for R/R MCL. R/R MCL is a complex disease with many therapeutic options none of which has been proven superior in head-to-head comparison. In this review, the current treatment strategies are recapped, evolving agents are discussed, and we provide guidance in treating R/R MCL.

New Directions for Mantle Cell Lymphoma in 2022

Mantle cell lymphoma is a rare B-cell non-Hodgkin lymphoma that is clinically and biologically heterogeneous. Risk stratification at the time of diagnosis is critical. One of the most powerful prognostic indices is the Mantle Cell Lymphoma International Prognostic Index-Combined, which integrates an estimate of proliferation (Ki67 index) with the standard Mantle Cell Lymphoma International Prognostic Index clinical factors. In addition, the presence of TP53 mutation is associated with suboptimal response to intensive chemoimmunotherapy and particularly dismal survival outcomes. Given their excellent activity in the relapsed/refractory setting, increasingly, biologically targeted therapeutics-such as covalent Bruton tyrosine kinase inhibitors, lenalidomide, and venetoclax-are being incorporated into "chemotherapy-free" regimens and in combination with established chemoimmunotherapy backbones for treatment-naïve mantle cell lymphoma. In addition, risk-adapted treatment programs are increasingly being studied. These programs tailor treatment according to baseline prognostic factors (e.g., presence of TP53 mutation) and may incorporate biomarkers of response such as minimal residual disease assessment. Although still investigational, these studies present an opportunity to move beyond the biology-agnostic, historical fitness-based treatment selection paradigm and toward a more personalized, tailored treatment approach in mantle cell lymphoma. After Bruton tyrosine kinase inhibitor failure, many promising standard or investigational therapies exist, including CAR T-cell therapy (including brexucabtagene autoleucel and lisocabtagene maraleucel), bispecific antibody therapy targeting CD20-CD3, zilovertamab vedotin (an antibody-drug conjugate that targets ROR1), and the noncovalent Bruton tyrosine kinase inhibitor pirtobrutinib. These new therapies show promising efficacy, even among high-risk patients, and will likely translate to improvements in survival outcomes for patients with progressive mantle cell lymphoma following treatment with a Bruton tyrosine kinase inhibitor.

Real-World Treatment Patterns and Outcomes of Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is considered incurable with the available chemoimmunotherapy approaches, and therefore newer, effective targeted therapies such as Bruton Tyrosine Kinase (BTK) inhibitors are increasingly used in MCL as chronic suppressive therapy, especially in the elderly. We aimed to describe the treatment patterns in MCL at different lines of therapy with a focus on BTK inhibitor use and compare outcomes with known prognostic factors using a nationwide Flatiron Health electronic health record (EHR)-derived de-identified database. We analyzed patient-level data from the period of 2011 to 2021. In this study of 4336 patients with MCL, we found that bendamustine plus rituximab chemotherapy was the most commonly used frontline regimen (42%). Maintenance rituximab or consolidative autologous stem cell transplant (ASCT) was administered to 31% of all patients. Also, for patients who received ASCT as consolidation therapy, only 34% subsequently received rituximab maintenance. BTK inhibitors were the most preferred agents in second or later lines of therapy (n=933, 57%), followed by bortezomib, lenalidomide, and venetoclax, respectively. Among patients treated with BTK inhibitors, the median real-world overall survival (rwOS) was 35 months (95%CI 27-50), 24 months (95%CI 22 - 30), and 18 months (95% CI 14 - 21), for first line, second line and for third or later line of therapy, respectively. Patients with deletion 17p/TP53 mutation and blastoid variant MCL had poor outcomes; however, BTK inhibitors appeared to mitigate the negative influence of del17p/TP53 mutated MCL with an HR of 1.17 (95%CI 0.88 - 1.55) on multivariable analysis.

IBRORS-MCL study: a Spanish retrospective and observational study of relapsed/refractory mantle-cell lymphoma treated with ibrutinib in routine clinical practice

This retrospective study evaluated 66 patients diagnosed with relapsed and/or refractory mantle cell lymphoma (R/R MCL) treated with ibrutinib in Spain in routine clinical practice. At diagnosis, patients had a median age of 64.5 years, 63.6% presented with intermediate/high sMIPI (simplified prognostic index for advanced-stage mantle cell lymphoma), 24.5% had the blastoid variant, and 55.6% had a Ki67 > 30%. Patients had received a median of 2 prior lines of therapy (range 1-2; min-max 1-7). Overall response rate was 63.5%, with 38.1% of patients achieving complete response (CR). With a median duration of ibrutinib exposure of 10.7 months (range 5.2-19.6; min-max 0.3-36), the median progression-free survival (PFS) and overall survival (OS) were 20 months [95% confidence interval (CI) 8.8-31.1] and 32 months (95% CI 22.6-41.3), respectively, and were not reached in patients achieving CR. No grade ≥ 3 cardiovascular toxicity or bleeding was reported. This study supports that treatment with ibrutinib leads to high response rates and favorable survival outcomes in patients with R/R MCL.

Mantle cell lymphoma in 2022-A comprehensive update on molecular pathogenesis, risk stratification, clinical approach, and current and novel treatments

The field of mantle cell lymphoma (MCL) has witnessed remarkable progress due to relentless advances in molecular pathogenesis, prognostication, and newer treatments. MCL consists of a spectrum of clinical subtypes. Rarely, atypical cyclin D1-negative MCL and in situ MCL neoplasia are identified. Prognostication of MCL is further refined by identifying somatic mutations (such as TP53, NSD2, KMT2D), methylation status, chromatin organization pattern, SOX-11 expression, minimal residual disease (MRD), and genomic clusters. Lymphoid tissue microenvironment studies demonstrated the role of B-cell receptor signaling, nuclear factor kappa B (NF-kB), colony-stimulating factor (CSF)-1, the CD70-SOX-11 axis. Molecular mechanism of resistance, mutation dynamics, and pathogenic pathways (B-cell receptor (BCR), oxidative phosphorylation, and MYC) were identified in mediating resistance to various treatments (bruton tyrosine kinase (BTK) inhibitors [ibrutinib, acalabrutinib]. Treatment options range from conventional chemoimmunotherapy and stem cell transplantation (SCT) to targeted therapies against BTK (covalent and noncovalent), Bcl2, ROR1, cellular therapy such as anti-CD19 chimeric antigen receptor therapy (CAR-T), and most recently bispecific antibodies against CD19 and CD20. MCL patients frequently relapse. Complex pathogenesis and the management of patients with progression after treatment with BTK/Bcl2 inhibitors and CAR-T (triple-resistant MCL) remain a challenge. Next-generation clinical trials incorporating newer agents and concurrent translational and molecular investigations are ongoing.

Bendamustine or high-dose cytarabine-based induction with rituximab in transplant-eligible mantle cell lymphoma

The objective of this study was to explore differences in outcomes between first-line R-B and R-CHOP/R-DHAP in transplant-eligible patients with MCL. A population-based cohort of 97 patients aged 18-65 years with stage II-IV MCL, consecutively treated with R-B was retrospectively identified at BC Cancer. Baseline characteristics, response rates, and outcomes were compared to the cohort of 232 MCL patients randomized to the R-CHOP/R-DHAP arm of the MCL Younger trial. The primary aim was to estimate the hazard ratio (HR) of the progression-free survival (PFS) comparison between both groups, adjusted for MCL International Prognostic Index (MIPI), Ki67 index, and blastoid/pleomorphic morphology. Secondary endpoints included response rate, event free survival, overall survival, and time to next treatment. Ann Arbor stage, lactate dehydrogenase, MIPI, blastoid morphology, and MCL35 assignments were similar between both groups. The overall response rate (ORR) to R-B was 90% (54% complete response [CR]); 77% of patients proceeded to autologous stem cell transplantation (ASCT) and 78% received maintenance rituximab (MR). The ORR to R-CHOP/R-DHAP was 94% (54% CR); 78% proceeded to ASCT and 2% received MR. There were no differences in PFS in unadjusted (HR 0.87 [95% CI 0.53-1.41], p=0.56) or adjusted (HR 0.79 [95% CI 0.45-1.37], p=0.40) comparisons. There were no clear differences in secondary endpoints in unadjusted or adjusted analyses. This retrospective adjusted comparison of two independent cohorts of younger patients with MCL suggests that R-B with ASCT and maintenance rituximab is a feasible and effective first-line treatment, with outcomes comparable to R-CHOP/R-DHAP with ASCT.

Stem cell transplant for mantle cell lymphoma in Taiwan

Mantle cell lymphoma (MCL) is a B-cell lymphoma featuring an aggressive course and a progressive relapsing pattern. International guidelines recommend early consolidative autologous stem cell transplant (auto-SCT) for eligible patients while reserving allogeneic SCT (allo-SCT) as therapy for refractory cases. Since data describing the implementation of transplants in the Asian population with MCL are limited, we aimed to analyze post-SCT outcomes of 99 MCL patients from the Taiwan Bone Marrow Transplant Registry database. The median age was 56 years, and 11% of the patients had blastoid variant MCL. Ninety-four patients received auto-SCT, while 13 patients received allo-SCT, eight of which received allo-SCT after failing auto-SCT. Before auto-SCT, 52% of the patients were in their first complete remission (CR1). Overall, 37 patients (39%) relapsed after auto-SCT. The median post-auto-SCT progression-free survival and overall survival (OS) were 43.6 months and not reached, respectively. Blastoid variant MCL, transplant not received in CR1, and disease progression within 12 months post-auto-SCT independently predicted inferior OS in multivariable analysis. The median post-allo-SCT OS was 74 months. Two patients (15%) died of MCL recurrence post-allo-SCT. Three patients with refractory diseases were salvaged with ibrutinib or venetoclax to allo-SCT. Treatment strategies incorporating novel agents warrant further optimization.

Use of BTK inhibitors with focus on ibrutinib in mantle cell lymphoma: an expert panel opinion statement

The introduction of BTK inhibitors transformed the management of patients with mantle cell lymphoma (MCL). Ibrutinib, the first-in-class BTK inhibitor is now approved in more than 80 countries and there are over 20 new BTK inhibitors in development. In addition, novel agents show potential clinical activity (alone and in combination) and are in the approval phase and/or being studied in ongoing clinical trials. How does the practicing clinician decide on the optimal therapeutic strategy for this highly heterogenous disease? In July 2020 a group of experts from Italy, convened a meeting to address and provide clarification on a series of outstanding issues in the treatment of MCL with the view of providing clinical guidance on its management. This expert opinion statement represents the panel's collective analysis, evaluation, and recommendations and is made up of a series of questions and answers (in the form of a review of the pertinent literature) designed to replicate those posed by practicing clinicians in Italy but which are applicable to clinical settings worldwide. This article is protected by copyright. All rights reserved.

Evolving frontline immunochemotherapy for mantle cell lymphoma and the impact on survival outcomes

Because there have been a dvances in frontline treatment for mantle cell lymphoma (MCL) over the last 2 decades, we sought to characterize the changes in frontline treatment patterns and their association with outcomes. Patients with newly diagnosed MCL from September 2002 through June 2015 were enrolled in a prospective cohort study, and clinical characteristics, treatment, and clinical outcomes were compared between patients diagnosed from 2002 to 2009 (Era 1) compared with 2010 to 2015 (Era 2). Patient age, sex, and simplified MCL International Prognostic Index (sMIPI) score were similar between the 2 groups. In patients age 65 years or younger, there was less use of rituximab plus hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (R-Hyper-CVAD) (16.1% vs 8.8%) but more use of rituximab plus maximum-strength cyclophosphamide, doxorubicin, vincristine, and prednisone (R-maxi-CHOP) alternating with rituximab plus high-dose cytarabine (R-HiDAC), also known as the Nordic regimen, and R-CHOP alternating with rituximab plus dexamethasone, high-dose cytarabine, and cisplatin (R-DHAP) (1.1% vs 26.4%) and less use of R-CHOP or R-CHOP-like regimens (64.5% vs 35.2%) but more use of R-bendamustine (0% vs 12.1%) in Era 2 (P < .001). These changes were associated with improved event-free survival (EFS; 5-year EFS, 34.3% vs 50.0%; P = .010) and overall survival (OS; 5-year OS, 68.8% vs 81.6%; P = .017) in Era 2. In patients older than age 65 years, there was less use of R-CHOP or R-CHOP-like therapy (39.0% vs 14.3%) and nonstandard systemic therapy (36.6% vs 13.0%) but more use of R-bendamustine (0% vs 49.4%). These changes were associated with a trend for improved EFS (5-year EFS, 25.4% vs 37.5%; P = .051) in Era 2. The shift from R-CHOP or R-CHOP-like regimens to R-bendamustine was associated with improved EFS (5-year EFS, 25.0% vs 44.6%; P = .008) in Era 2. Results from this prospective cohort study provide critical real-world evidence for improved outcomes with evolving frontline patterns of care in patients with MCL.

Circulating Tumor DNA Predicts Therapeutic Outcome in Mantle Cell Lymphoma

Early changes in ctDNA dynamics are prognostic in untreated MCL.

Bortezomib maintenance after bortezomib-based induction therapy does not improve outcome in untreated MCL.

Mantle cell lymphoma (MCL) is biologically and clinically heterogeneous and would benefit from prognostic biomarkers to guide management. Circulating tumor DNA (ctDNA) is a novel prognostic biomarker in diffuse large B-cell lymphoma that may have applicability in MCL. We analyzed ctDNA dynamics in previously untreated patients with MCL who received induction therapy with bortezomib and DA-EPOCH-R for 6 cycles followed by random assignment to observation or bortezomib maintenance in responding patients in a prospective phase 2 study. Most patients also underwent initial treatment window of bortezomib alone prior to induction. Serum was collected pretreatment, after the window, after cycles 1 and 2, at the end of induction, and at each follow-up visit along with restaging computed tomography scans. Next-generation sequencing was used to identify and quantify ctDNA encoding the immunoglobulin receptor sequences in serum as markers of minimal residual disease. Fifty-three patients were enrolled, with a median follow-up of 12.7 years. Patients without detectable ctDNA after 2 cycles of induction had longer progression-free survival (PFS) and overall survival (OS) compared with those with detectable ctDNA (median PFS, 2.7 vs 1.8 years; overall P = .005; median OS, 13.8 vs 7.4 years; overall P = .03). Notably, in vivo assessment of ctDNA dynamics during the bortezomib window was not prognostic, and there was no difference in PFS or OS with bortezomib maintenance. ctDNA monitoring after induction showed that molecular relapse preceded clinical relapse in some cases. In conclusion, interim ctDNA negativity strongly correlates with improved survival and supports the investigation of response-adapted strategies. This trial was registered at www.clinicaltrials.gov as #NCT00114738.

Initial Treatment Patterns and Survival Outcomes of Mantle Cell Lymphoma Patients Managed at Chinese Academic Centers in the Rituximab Era: A Real-World Study

Purpose

The aim of the study was to delineate the disease characteristics, the initial treatment patterns, and survival in patients with mantle cell lymphoma (MCL) managed in the real world.

Methods

Data of 518 MCL patients from 5 major Chinese Hematology Centers in the period from 2007 to 2017 were retrospectively analyzed.

Results

The median age was 58 years. Of the patients, 88.6% had Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0–1 and 80.7% had advanced-stage disease. Ki67 expression was <30% in 39.6% of the patients, and 43.2% of patients were categorized into a low-risk group based on the Mantle Cell Lymphoma International Prognostic Index (MIPI) scoring system. Overall, 73.4% of the patients received rituximab as their first-line therapy. The most commonly used chemotherapy was the CHOP-like (cyclophosphamide, hydroxydaunomycin, oncovin, and prednisone) regimen (45.2%), followed by high-dose cytarabine-containing chemotherapy (31.3%) and bendamustine (3.3%). Of the patients, 13.7% (n = 71) underwent consolidative autologous stem cell transplantation (ASCT), and 19.3% (n = 100) received novel agents containing first-line regimens. With a median follow-up time of 52 months, the 3- and 5-year overall survival (OS) rates were 73.7% and 61.4%, respectively. Age ≤60 years, ECOG PS 0–1, stages I–II, normal lactate dehydrogenase (LDH), absence of bone marrow involvement, Ki67 <30%, and lower-risk IPI/MIPI scores were significantly associated with improved OS (p < 0.05). The inclusion of rituximab improved the 5-year OS, with borderline significance (62.5% vs. 55.2%, p = 0.076). High-dose cytarabine-containing chemotherapy showed significant clinical benefit in 5-year OS (72.1% vs. 55.9%, p = 0.010). Patients with ASCT had better 5-year OS in the younger (≤60 years) age group (87.2% vs. 64.8%, p = 0.002).

Conclusion

This large retrospective dataset unequivocally confirmed the survival advantage afforded by cytarabine-containing regimen and ASCT in a first-line setting under real-world management in the rituximab era.

New Indications and platforms for CAR-T therapy in lymphomas beyond DLBCL

CD19 directed chimeric antigen receptor T-cell therapy (CAR-T) represents a significant advancement for patients with relapsed/refractory large B-cell lymphoma (LBCL). Long term follow-up confirms durable remissions in nearly half of the patients, a population which was previously estimated to have a median survival of around 6 months with standard salvage therapy. This initial success of CAR-T has led to significant expansion across other lymphoma histologies resulting in the recent regulatory approval of CAR-T in mantle cell lymphoma and follicular lymphoma. Additionally, multiple novel platforms of CAR-T therapy are under development to improve efficacy and limit toxicity such dual antigen targeting, allogeneic and natural killer CAR's. In this review, we focus on the new indications of CAR-T in lymphomas beyond LBCL as well as emerging platforms of CAR-T therapy.